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Pure Appl. Chem., Vol. 69, No. 12, pp. 2489-2495, 1997.
PHYSICAL CHEMISTRY
DIVISION
COMMISSION ON MOLECULAR STRUCTURE AND SPECTROSCOPY
Parameters and Symbols
for Use in Nuclear Magnetic Resonance
(IUPAC Recommendations 1997)
A. NMR EXPERIMENTAL PARAMETERS for reporting in publications
1. Introduction
The aim of this list is to introduce a degree of uniformity in the
way in which NMR results are reported in chemical journals, so as to
ensure that experiments can be precisely repeated. It is to be regarded
as a minimal list, though not all parameters are relevant to a given
experiment. It should be noted that sample conditions (e.g. solvent,
concentration etc.) are not part of the list, though clearly it is also
essential for these to be specified.
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2. General
- The nucleus or nuclei studied.
- The instrument manufacturer and model.
- The resonance frequency or frequencies (preferably of the reference
sample or samples).
- The magnetic field [optional if frequencies are given].
- The type(s) of pulse sequence.
- The referencing procedure for obtaining chemical shifts (and/or
relative shielding constants).
- The size/nature of the sample tube/container.
- The temperature of the sample at the time of the measurement.
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3. Pulse conditions
- The RF pulse magnetic field (or equivalent in frequency
units) and/or equivalent 90o pulse
duration. [Note the unambiguous word "duration" rather than "width"
or "length".]
- The flip (nutation) angle(s) and relative phases of all pulses.
- The spectral width (or dwell time if unambiguously defined).
- The acquisition time (or number of acquired data points if the
dwell time is given).
- The number of transients (acquisitions).
- The recycle delay. [Note, this implies the time interval between
the completion of one cycle of a pulse sequence and the start of the
next one, sometimes called a relaxation delay. This is distinct from
a cycle time, which is the time between analogous points of successive
pulse sequence cycles].
- Any other relevant time intervals.
- The decoupling or double/multiple resonance method and conditions,
including the RF magnetic field (or equivalent in frequency units
and/or equivalent 90o pulse duration).
- Pulse shapes and relevant frequencies (for experiments with selective
pulses).
- The magnitudes, directions, shapes and durations of any magnetic
field gradients.
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4. Processing parameters
- Zero-filling extent.
- Any window function (apodization, pre-acquisition delay, resolution
enhancement, line broadening).
- Any special baseline correction or phase adjustment procedures.
- Any additional processing details, such as linear prediction or
maximum entropy.
- Any special procedures for signal quantification (e.g. deconvolution).
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5. Solid-state spectra (additional requirements)
- Contact time. [For cross polarization operation.]
- Sample rotation angle.
- Sample rotation rate.
- Use of special techniques such as DOR or DAS.
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6. Relaxation measurements (additional
requirements)
- Number of measurement points used.
- Analysis method (exponential etc.).
- Radiofrequency field magnitude (or equivalent expressed in frequency
units). [For T1r measurements.]
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7. Multidimensional spectra
- The time increments and the number of data points and/or
the spectral width and maximum duration of evolution periods must
be given for each dimension, as well as the data size after processing.
- For figures of multidimensional spectra, each axis should be unambiguously
labelled by the variable involved (e.g. dH,
dC, JCH)
where possible, as well as by a frequency label such as F1,
F2 etc.
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8. Additional notes
- Figures of spectra should have an indication of the direction of
increasing frequency and the captions should state the nucleus involved.
Wherever feasible, assignments of chemical shifts should be indicated
on illustrated spectra.
- Phase cycling of all RF pulses and of the receiver should be specified
when crucial to the experiment.
- For novel or unusual pulse sequences a timing diagram is highly
recommended. If acronyms are used instead of diagrams for established
sequences, a literature reference is recommended.
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Page last modified 13 July 1999.
Copyright ©1997, 98, 99 International Union of Pure and Applied
Chemistry.
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